In this case study, we show how DOE's Best Practices Guide For Residential HVAC Retrofits works - as well
as some of the installation practice and building code official problems that can arise.

Traditionally, retrofits are done in a piecemeal fashion; individual building components are replaced one at a time, with little thought given to their interactions.This is particularly true for HVAC systems, whose performance can be negatively affected by changes in the building envelope.The systems approach, which attempts to treat the whole building and all of its components together, is a good solution to this problem, and has three major benefits: • correct system sizing when loads (such as envelope conduction, window solar gain, and infiltration) are reduced by retrofits, • avoidance of potential problems (such as increased condensation potential when air conditioning is added to previously uncooled houses), and • total cost can be reduced.The cost of a retrofit using the systems approach is often less than the sum total of the individual retrofits. Because the current retrofit industry is not structured to use the systems approach, the DOE Best Practices Guide For Residential HVAC Retrofits was developed to provide guidance for contractors. In order to simplify the ...